// This test attempts to verify that the set of 'native'
// certificates produced by this crate is roughly similar
// to the set of certificates in the mozilla root program
// as expressed by the `webpki-roots` crate.
//
// This is, obviously, quite a heuristic test.

use std::collections::HashMap;
use ring::io::der;
use untrusted;

fn stringify_x500name(subject: &[u8]) -> String {
    let mut parts = vec![];
    let mut reader = untrusted::Reader::new(subject.into());

    while !reader.at_end() {
        let (tag, contents) = der::read_tag_and_get_value(&mut reader)
            .unwrap();
        assert!(tag == 0x31); // sequence, constructed, context=1

        let mut inner = untrusted::Reader::new(contents.into());
        let pair = der::expect_tag_and_get_value(&mut inner, der::Tag::Sequence)
            .unwrap();

        let mut pair = untrusted::Reader::new(pair.into());
        let oid = der::expect_tag_and_get_value(&mut pair, der::Tag::OID)
            .unwrap();
        let (valuety, value) = der::read_tag_and_get_value(&mut pair)
            .unwrap();

        let name = match oid.as_slice_less_safe() {
            &[0x55, 0x04, 0x03] => "CN",
            &[0x55, 0x04, 0x05] => "serialNumber",
            &[0x55, 0x04, 0x06] => "C",
            &[0x55, 0x04, 0x07] => "L",
            &[0x55, 0x04, 0x08] => "ST",
            &[0x55, 0x04, 0x09] => "STREET",
            &[0x55, 0x04, 0x0a] => "O",
            &[0x55, 0x04, 0x0b] => "OU",
            &[0x09, 0x92, 0x26, 0x89, 0x93, 0xf2, 0x2c, 0x64, 0x01, 0x19] => "domainComponent",
            &[0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x09, 0x01] => "emailAddress",
            _ => panic!("unhandled x500 attr {:?}", oid)
        };

        let str_value = match valuety {
            // PrintableString, UTF8String, TeletexString or IA5String
            0x0c | 0x13 | 0x14 | 0x16 => std::str::from_utf8(value.as_slice_less_safe()).unwrap(),
            _ => panic!("unhandled x500 value type {:?}", valuety)
        };

        parts.push(format!("{}={}", name, str_value));
    }

    parts.join(", ")
}

fn to_map<'a>(anchors: &'a [webpki::TrustAnchor<'a>]) -> HashMap<Vec<u8>, &'a webpki::TrustAnchor<'a>> {
    let mut r = HashMap::new();

    for anchor in anchors {
        r.insert(anchor.spki.to_vec(), anchor);
    }

    r
}

#[test]
fn test_does_not_have_many_roots_unknown_by_mozilla() {
    let native = rustls_native_certs::load_native_certs()
        .unwrap();
    let mozilla = to_map(webpki_roots::TLS_SERVER_ROOTS.0);

    let mut missing_in_moz_roots = 0;

    for cert in &native.roots {
        let cert = cert.to_trust_anchor();
        if let Some(moz) = mozilla.get(cert.spki) {
            assert_eq!(cert.subject, moz.subject,
                       "subjects differ for public key");
        } else {
            println!("Native anchor {:?} is missing from mozilla set", stringify_x500name(cert.subject));
            missing_in_moz_roots += 1;
        }
    }

    let threshold = 0.5; // no more than 50% extra roots
    let diff = (missing_in_moz_roots as f64) / (mozilla.len() as f64);
    println!("mozilla: {:?}", mozilla.len());
    println!("native: {:?}", native.len());
    println!("{:?} anchors present in native set but not mozilla ({}%)", missing_in_moz_roots, diff * 100.);
    assert!(diff < threshold, "too many unknown roots");
}

#[test]
fn test_contains_most_roots_known_by_mozilla() {
    let native = rustls_native_certs::load_native_certs()
        .unwrap();

    let mut native_map = HashMap::new();
    for anchor in &native.roots {
        native_map.insert(anchor.to_trust_anchor().spki.to_vec(), anchor);
    }

    let mut missing_in_native_roots = 0;
    let mozilla = webpki_roots::TLS_SERVER_ROOTS.0;
    for cert in mozilla {
        if native_map.get(cert.spki).is_none() {
            println!("Mozilla anchor {:?} is missing from native set", stringify_x500name(cert.subject));
            missing_in_native_roots += 1;
        }
    }

    #[cfg(windows)]
    let threshold = 0.95; // no more than 95% extra roots; windows misses *many* roots
    #[cfg(not(windows))]
    let threshold = 0.5; // no more than 50% extra roots

    let diff = (missing_in_native_roots as f64) / (mozilla.len() as f64);
    println!("mozilla: {:?}", mozilla.len());
    println!("native: {:?}", native.len());
    println!("{:?} anchors present in mozilla set but not native ({}%)",
             missing_in_native_roots, diff * 100.);
    assert!(diff < threshold, "too many missing roots");
}

#[test]
fn util_list_certs() {
    let native = rustls_native_certs::load_native_certs()
        .unwrap();

    for (i, cert) in native.roots.iter().enumerate() {
        println!("cert[{}] = {}", i, stringify_x500name(cert.to_trust_anchor().subject));
    }
}
